Domestic appliance



@ci 3G, 195i W C. CRIMMlNS 573,409

DOMESTIC PPLIANCE Filed June 2, 1948 2 SHEETS-SHEET l A; IN I/ LN TOR.,

@Ch 36, 1951 W CRlMMgNg, 2,573,409

DOMESTIC PPLIANCE Filed June 2, 1948 y 2 SHEETS-SHEET 2 Patented Oct. 30, 1951 DOMESTIC APPLIANCE William C. Crimmins, Van Buren, Ind., assignor to General Motors Corporation, Dayton, Ohio, a

corporation of Delaware Application June 2, 1948, Serial No. 30,595

Claims. l

This invention relates to a domestic appliance and more particularly to a movable control having a shifting holding station.

It is an object of my invention to provide a simple, reliable, inexpensive mechanism which will provide a resilient holding station at one point in one direction of movement Without any holding at that point in the return movement.

It is another object of my invention to provide a simple, reliable, inexpensive mechanism providing a resilient holding station at one point in one direction of movement and transferring the said holding station to a second point in the return direction of movement.

It is another object of my invention to provide a simple, reliable, inexpensive mechanism providing a resilient holding station which is reset to another position by the continuance of the movement of a control.

To attain these objects I provide a set of carnoperated control devices adapted to be operated in one direction by a knob and in the return direction by a spring-wound clock mechanism. A primary detent is provided on the operating shaft having a projection capable of entering a notch in a second rockable detent which is resiliently held in either of two positions. The two positions of the secondary detent are arranged so that the notch can be entered on one side in one direction of movement and from the opposite side in a second direction of movement. When the projection strikes the far side of the notch the second detent is turned to the second position so that upon the return movement, the projection can freely enter the notch and engage the far side.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. l is a view, partly diagrammatic, disclosing in the off position the control devices and the detent mechanism embodying one form of my invention;

Fig. 2 is a view similar to Fig. 1 disclosing in the simmer heat position the control devices and the detent mechanism;

Fig. 3 is a view similar to Figs. 1 and 2 disclosing in one of the high heat positions the control device and the detent mechanism; and

' Fig. 4 is a vertical sectional view through the structural embodiment of the control device and detent mechanism.

Referring now to the drawings and more palticularly to Fig. 1, there is shown a control knob 20 adapted to cooperate with a pointer 22. This control knob is mounted upon the front end of an operating shaft 24 indicated in the diagrammatic views by a dot and dash line. This operating shaft 24 has a wide flat on one side and a bead on the fiat on the opposite side so that the primary detent member 26 and the operating members 28, 30, 32 and 34 may be properly assembled on the shaft in the correct orientation with the control knob 20.

At the far end of the operating shaft 24 there is provided a clock mechanism 36 of the springwound type wherein, when the shaft is turned in a clockwise direction the clock spring is wound and when the control knob 2D is released there is a tendency for the spring to unwind and drive the operating shaft 24 and the control knob 20 in a counterclockwise direction at a uniform rate of speed. A friction spring clutch i s also provided between the clock mechanism 36 and the operating shaft to make it possible for the control knob 20 and the operating shaft 24 to be turned in either direction manually without damaging the clock mechanism. A friction spring clutch of a type suitable for use in this device is illustrated in the Rhodes Patent 2,434,471 issued Jan. 13, 1948.

My invention is applicable to control devices of various types, such as the switches and the valves. For the purpose of illustrating my invention I have shown control devices in the form of switch mechanisms connected for the control of a two-element electrical heating unit such as might be used for a deep well cooker in an electric range. For example, there is illustrated a heating unit 38 having a rating of 800 watts upon a voltage of 235 volts, and a second heating unit 40 having a rate of 500 watts at 117 volts.

The adjacent terminals of these heating units 38 and 4|] are connected to the movable reed element 42 of a double-throw switch mechanism which includes stationary contacts 44 and 46. The movable element 42 is moved into engagement with either of these stationary contacts 44 and 46 or out of engagement with both contacts by the cam 32. The opposite end of the heating unit 38 is connected to the movable reed element 48 operated by the cam 34 into and out of engagement with the stationary contact 50. The remaining terminal of the heating unit 40 is connected to the movable reed element 52 having contacts at its lower end cooperating with the stationary contacts 54 and 56.

The movable reed element 52 is operated by 24 and the control knob 20 under the force of the spring of the clock mechanism 36 will cont-inue until the projection 23 engages the projection |49 upon the far side of the notch |3|. This engagement is made approximately at the same time that the projection |2| engages the roller knob 2E) from the "simmer to either the low, medium high or off positions. Continuing the movement following the engagement, will cause the projection |23 to carry the projection |49 out of its path and in so doing will pivot the secondary detent |21 until the notch |33 is again engaged by the projection |35. This therefore removes the notch |49 from the path of the projection |23 so that when the control knob is later to be moved into the simmer position theY projection |23 can again freely enter the notch 3| to engage the projection |25 upon the far side of the notch |3|.

As is better shown in Fig. 4, the projections 80, 96 and |2| are made lesser in width than the projection |23. The purpose of this is to prevent interference between the projections 80, 96 and |2| with the secondary detent |21 and its projections |25 and |49 which would otherwise interfere in the position shown in Fig. 3. The projection |23, however, is made sufficiently wide that it does engage the secondary detent |21.

The structure of the case is shown in Fig. 4. The case 2| is made of a plastic electrical insulating material and contains a cavity receiving the clock mechanism 36 which is enclosed by a thin metal plate |5I. The movable reed switch elements 42 and 48, and 52 and 58 are mounted upon opposite side walls of the case. The cams 28, 33, 32 and 34 are preferably formed from a single piece of plastic molded upon the shaft 24. A connector |53 connects the rear end of the cam piece with the clock mechanism 36. The entire detent mechanism is mounted between the detent plate |55 and the mounting bracket |51 which are fastened to the front face of the case 2|. The pivot studs |29, |39 and 86 and the stop stud 92 and the spring stud |45, are all held within apertures provided in both the detent plate |55 and the mounting bracket |51. Suitable shoulders on each prevent any axial movement. The construction is inexpensive and reliable.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, as may come Within the scope of the claims` which follow.

What is claimed is as follows:

1. A control including a movable shaft means, a control device operated by the operation of said shaft means, said shaft means being provided with a primary detent means having a projection, a pivoted rockable secondary detent means having two spaced projections, said spaced projections having sufficient length and spread to alternately present themselves at two different locations in the path of movement of the primary detent projection, and resilient holding means for said secondary detent means, said resilient holding means and said secondary detent means having cooperating means providing two holding stations for holding either of the spaced projections alternately in the path of movement of the projection of the primary detent means.

2. A control including a movable shaft means, a control device operated from a first control position to a second control position at one predetermined point in the movement of the shaft means, said shaft means being provided with a primary detent means having a projection movable with the shaft means and having a fixed relationship to said predetermined point, a pivoted rockable secondary detent means having two spaced projections, said projections having sufcient length and spread to alternately present themselves at two different locations in the path of movement of the primary detent projection, said secondary detent means and one of its projections being so located relative to the primary detent means and its projection that their engagement takes place substantially at said predetermined point in the movement of the shaft means at which the control device is operated from one position to another.

3. A control including a movable shaft means, a control device operated from a first control position to a second control position at one predetermined point in the movement of the shaft means, said shaft means being provided with a primary detent means having a projection movable with the shaft means and having a fixed relationship to said predetermined point, a pivoted rockable secondary detent means having two spaced projections, said projections having sunicient length and spread to alternately pressent themselves at two different locations in the path of movement of the primary detent projection, said secondary detent means and one of its projections being so located relative to the primary detent means and its projection that their engagement takes place substantially at said predetermined point in the movement of the shaft means at which the control device is operated from one position to another, said shaft means being provided with manual manipulating means whereby it may be moved in one direction to engage and move said one secondary detent projection out of the path of said primary detent projection in coordination with the movement of the control device from the first position to the second, and timing drive means for moving the shaft means in the opposite direction at a timed rate of movement through a point at which the control device is operated from the second position to the first position and continuing until the primary detent projection engages the second secondary detent projection.

4. A control including a movable shaft means, a control device operated to three different control positions in three different positions of the shaft means, said shaft means being provided with a resilient primary detent means including a projection and notch arrangement synchronized with two of said three different positions of said shaft means, a rockable secondary detent means provided with a notch, said primary detent means being provided with an additional projection of sufficient length to extend into said notch, a resilient two position holding means for holding said secondary detent means in either of two holding positions in which opposite sides of said notch are presented for engagement by said additional projection, said additional projectionbeing oriented relative to the shaft means and one of the holding positions of said notch so that its engagement with one side of the notch is synchronized with the arrival of the shaft in the third of the three different positions of the shaft means.

5. A control including a reversible rotatable 7 shaft means, `a. spring means for turning-Said shat means :in one direction, means for turning the shaft means in the ODPQite direction and Winding up said spring means, said shaft means being provided With a projection, a rockable detent means having a pivoting axis parallel to and suioiently near to said shaft means to be in the path of said projection, said detent means including a rockable member having la notch with shoulders upon opposite sides of the notch, said detent means also including a snap acting resilient holding means for resiliently holding said rockable member lin either of two stations, said rockable member in one of said stations having the rst of said shoulders out of the path of said projection and having the notch and the second shoulder in one location in the path of said projection for stopping said shaft means in a lfirst location in one direction of rotation, said rockable member in the second REFERENCES CITED The following references are of record in the le of this patent:

UNITED vSTATES PATENTS Number Name Date 2,409,762 Janes Oct. 22, 1946 .2,470,274 Wahlberg May 17, 1949 FOREIGN PATENTS Number Country Date Y281,026* Great Britain Nov. 30,1927 

